neurology- Cognitive(executive function)

What are executive functions?

higher-level cognitive processes involved in planning, decision making, problem solving, and goal pursuit.

Which part of the brain is associated with executive functions?

The frontal lobe, particularly the prefrontal cortex

In which disorders are deficits in executive functions commonly seen?

like Alzheimer’s disease and schizophrenia, affecting goal selection and distraction exclusion.

What are executive functions according to Miyake’s definition?

working memory, inhibition (self-control and impulse control), and flexibility/shifting.

What are value-based decisions?

involve choosing between objects or actions based on their associated rewards.

What factors are considered in value-based decision making?

Factors include weighing immediate gratification against long-term benefits and assessing short-term and long-term consequences.

What is decision making in the context of the prefrontal cortex?

the mental process of measuring and comparing preferences to select the best option.

What is a value signal in brain activity?

correlates with the perceived value or preference of different options.

Where is a value signal found in the brain related to decision making?

ventromedial prefrontal cortex (vmPFC)

Executive Functions: Inhibition

• Ability to control attention, behavior, thoughts, and emotions.

• Includes self-control, impulse control, interference control.

• Necessary for resisting temptations and maintaining focus

Executive Functions: Working Memory

• Ability to hold and manipulate information in mind.

• Essential for tasks requiring monitoring and updating information.

• Examples: Mental arithmetic, following complex instructions.

Executive Functions: Flexibility

• Capacity to switch between tasks or mental sets.

• Adapt to new situations and view problems from multiple perspectives.

• Critical for changing strategies or adjusting to new rules.

Definition of Executive Dysfunction

• Impairment in abstract thinking, planning, problem-solving, and synthesizing information.

• Difficulty in starting, continuing, and stopping complex behavior.

Symptoms of Executive dysfunctions

• Challenges in understanding complex concepts.

• Struggles with organizing thoughts and actions.

• Problems with integrating information.

• Disorganized or erratic actions.

How is the prefrontal cortex connected to the mediodorsal (MD) nucleus of the thalamus relevant?

• facilitates the integration and processing of sensory and cognitive information, crucial for executive functions like attention, working memory, and decision-making.

the presence of a granular layer in the prefrontal cortex indicate:

• advanced cognitive processing capabilities, involving functions such as planning, reasoning, and abstract thinking.

granular cortex

• Contains layer IV packed with "granular cells," which are neurons with small cell bodies. This layer is associated with higher cognitive functions.

agranular cortex

• lacks a distinct layer IV with small neurons and is typically involved in simpler processing tasks, often related to motor functions.

What are stimulus-reward (S-R) associations?

• involve learning that a specific stimulus leads to a reward, enabling adaptive behavior and outcome prediction.

Why are primates particularly good at learning new S-R associations?

• Primates have advanced cognitive functions and complex brain structures, especially in the prefrontal cortex, supporting flexible learning and problem-solving.

lobotomy

was a popular treatment for severe mental disorders. This surgical procedure involved severing connections in the prefrontal cortex to alleviate symptoms of certain psychiatric conditions. While it was believed to reduce distress, it often resulted in significant impairments in executive functions and personality changes due to the disruption of prefrontal cortex activity.

value-based decisions

• Decisions involving choices between objects or actions based on anticipated rewards, assessing potential benefits and consequences.

examples of value-based decisions involving objects?

• Selecting food items based on nutritional value or taste preferences, or choosing images that symbolize certain rewards.

Examples of value-based decisions involving actions

• Deciding whether to turn left or right at a crossroads by evaluating potential immediate or future rewards associated with each direction.

What is decision making in terms of cognitive processes?

A mental process of measuring and comparing preferences to evaluate options based on perceived value and potential outcomes

What is a value signal in the context of decision making?

• Brain activity that correlates with perceived value or preference for different options, helping assess and prioritize choices.

How does the prefrontal cortex contribute to decision making?

• It processes value signals, integrating information about preferences, risks, and rewards to guide choices and behavior.

Where are value signals processed in the brain during decision making?

ventromedial prefrontal cortex (vmPFC).

Role of vmPFC in decision making

integrates information about rewards, risks, and personal preference to guide devisions that maximize positive outcome

neural common currency

A common neural representation used by the brain to evaluate and compare different options by integrating diverse factors

• It addresses how the brain chooses between qualitatively different options, like staying in a lecture versus having a meal.

Which brain regions are involved in processing value signals related to preferences?

• The vmPFC, ventral striatum, posterior cingulate cortex, and hippocampus are involved in processing these value signals.

How does the value signal in the vmPFC support the neural common currency hypothesis?

• It suggests that the brain uses a common neural framework to evaluate and compare different stimuli, facilitating decision-making across varied contexts.

What does the value signal in the vmPFC reflect?

• It reflects individual preferences for different stimuli, such as faces, houses, and paintings.

How does the vmPFC contribute to decision making with subjective value?

• It integrates subjective value into decision-making, influencing choices based on personal preferences and contextual factors.

Subjective Value in vmPFC

• The vmPFC is responsible for processing value signals that reflect subjective value, which is the perceived worth or desirability of an option based on personal preferences or contextual information.